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Informix ontape problems - "could not fork server connection"

 
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Robin King_1
Regular Advisor

Informix ontape problems - "could not fork server connection"

I'm trying to do an informix restore to a new server, or existing databases.
When I issue the "ontape -r" command, I'm getting the error "could not fork server connection" and then it stops.

Is this a system resource issue or something else?

Thanks
16 REPLIES 16
Bill Hassell
Honored Contributor

Re: Informix ontape problems - "could not fork server connection"

Look at syslog (/var/adm/syslog/syslog.log) at the end to see if there are kernel messages with the same timestamp. Also look at the console (not a telnet login, the 'real' console). Some possibilities:

1. Maximum number of processes for a single user ID has been exceeded (hint: "ps -f -u informix | wc -l" or whatever user ontape is running under). Kernel parameter maxuproc limits this value to prevent runaways on test servers, bump up if needed)

2. Maximum memory needed by a process. Kernel parameter maxdsiz is usually way too low (about 64megs) and some processes may need hundreds of megs.

3. syslog and console error messages: "proc: table is full" means that kernel parameter nproc needs to be doubled in size.

4. syslog and console error messages: "file: table is full" means that kernel parameter nfile needs to be doubled in size.



Bill Hassell, sysadmin
Robin King_1
Regular Advisor

Re: Informix ontape problems - "could not fork server connection"

Thanks Bill

There's nothing on the console or in the syslog that would suggest any problems.
There only seems to be a max of 12 Informix processes running, and maxuprc is at 75.
maxdsiz is at 268MB.
Steve Lewis
Honored Contributor

Re: Informix ontape problems - "could not fork server connection"

You need to tune your kernel on the server that you are restoring onto, to be the same as the one which the backup was taken.

As Bill said, this is caused either by running out of NPROC, MAXUPRC, MAXFILES or NFILE on the system.
sar -v 1 1 will give you a quick indication on files in the system.

Informix requires higher than default values for shared memory, semaphore, processes and file parameters in the kernel, as is documented in the $INFORMIXDIR/release/en_us/0333/ ...machine_notes....txt file





JJ_4
Frequent Advisor

Re: Informix ontape problems - "could not fork server connection"

If you could provide the following it would help :

Informix Version
HP-UX Version
Details from the file mentioned by MSGPATH in the $ONCONFIG
Does the restore start at all (i.e. produce a list of dbspaces, chunks and backup information)
Where was the backup from (i.e. the machine you are restoring to or another)?
Is the Informix version the same for the backup as for the restore?
Can you run oncheck -pr before the restore?
Not enough Zappa makes you sad.
Robin King_1
Regular Advisor

Re: Informix ontape problems - "could not fork server connection"

I've tried amending the kernel parameters to match the original system, but it doesn't seem to have made much difference.

Informix Version = Informix Dynamic Server Version 7.31.FD7
HP-UX Version = B.11.11
MSGPATH = "
Tue Sep 14 11:07:34 2004

11:07:34 Event alarms enabled. ALARMPROG = '/apps/informix/dba/bin/alarmprog'
11:07:40 DR: DRAUTO is 0 (Off)
11:07:40 Informix Dynamic Server Version 7.31.FD7 Software Serial Number AAD#J342257
11:07:40 WARNING: Next backup of DBspace rootdbs must be level-0 backup.
11:07:40 WARNING: Next backup of DBspace mvp_dbspace must be level-0 backup.
11:07:40 Informix Dynamic Server Initialized -- Shared Memory Initialized.
11:07:40 Dataskip is now OFF for all dbspaces
11:07:40 Restartable Restore has been ENABLED
11:07:40 Recovery Mode"

The Restore does start, and I get the list of dbspaces and chunks, I'm asked if I want to continue restore? and then if I want to backup the logs?
The restore then bails.

Interestingly, if I then try top restart the restore straight away, it bails out straight away. I've just done an ipcs -m, and then an ipcrm -m on all informix instances, and the restore appears to be doing something now. I'll have to wait and see how it goes.

The backup was taken from another server than is running a different version of HP-UX and Informix.

I'' run the oncheck -pr, if this bails again.





Robin King_1
Regular Advisor

Re: Informix ontape problems - "could not fork server connection"

It failed again, but got further. This is what I did (sorry for the length):

# ipcs -m
IPC status from /dev/kmem as of Tue Sep 14 11:54:10 2004
T ID KEY MODE OWNER GROUP
Shared Memory:
m 0 0x411c0a4f --rw-rw-rw- root root
m 1 0x4e0c0002 --rw-rw-rw- root root
m 2 0x412034ee --rw-rw-rw- root root
m 3075 0x0c6629c9 --rw-r----- root root
m 4 0x06347849 --rw-rw-rw- root root
m 1541 0xffffffff --rw-r--rw- root root
m 8710 0x5e10000d --rw------- root root
m 13831 0x52574801 --rw-rw---- root informix
m 8 0x52574802 --rw-rw---- root informix
m 9 0x52574803 --rw-rw-rw- root informix
# ipcrm -m 13831
# ipcrm -m 8
# ipcrm -m 9
# ipcs -m
IPC status from /dev/kmem as of Tue Sep 14 11:54:32 2004
T ID KEY MODE OWNER GROUP
Shared Memory:
m 0 0x411c0a4f --rw-rw-rw- root root
m 1 0x4e0c0002 --rw-rw-rw- root root
m 2 0x412034ee --rw-rw-rw- root root
m 3075 0x0c6629c9 --rw-r----- root root
m 4 0x06347849 --rw-rw-rw- root root
m 1541 0xffffffff --rw-r--rw- root root
m 8710 0x5e10000d --rw------- root root
m 13831 0x00000000 D-rw-rw---- root informix
m 8 0x00000000 D-rw-rw---- root informix
m 9 0x00000000 D-rw-rw-rw- root informix

# su - informix
For copyright information, view /etc/copyright.hp
INFerbhat3:/apps/informix:: ontape -r

Please mount tape 1 on /dev/rmt/0m and press Return to continue ...

Archive Tape Information

Tape type: Archive Backup Tape
Online version: Informix Dynamic Server Version 7.31.UD4
Archive date: Fri Sep 10 07:14:42 2004
User id: informix
Terminal id: /dev/console
Archive level: 0
Tape device: /dev/rmt/1m
Tape blocksize (in k): 64
Tape size (in k): 23000000
Tape number in series: 1

Spaces to restore:1 [rootdbs ]
2 [mvp_dbspace ]

Archive Information

Informix Dynamic Server Copyright(C) 1986-1998 Informix Software, Inc.
Initialization Time 06/15/2002 09:30:08
System Page Size 2048
Version 6
Archive CheckPoint Time 09/10/2004 07:14:43

Dbspaces
number flags fchunk nchunks flags owner name
1 1 1 1 N rmix dbs info
2 2001 2 1 N T rmix dbs info
3 1 3 14 N rmix dbspace info


Chunks
chk/dbs offset size free bpages flags pathname
1 1 0 614400 147389 PO- /dev/rootdbs
2 2 0 393216 393163 PO- /dev/tempdbs
3 3 0 1048575 3 PO- /dev/mvpdbs01
4 3 0 1048575 2 PO- /dev/mvpdbs02
5 3 0 1048575 0 PO- /dev/mvpdbs03
6 3 0 1048575 5549 PO- /dev/mvpdbs04
7 3 0 1048575 101870 PO- /dev/mvpdbs05
8 3 0 1048575 1858 PO- /dev/mvpdbs06
9 3 0 1048575 2 PO- /dev/mvpdbs07
10 3 0 1048575 26786 PO- /dev/mvpdbs08
11 3 0 1048575 15497 PO- /dev/mvpdbs09
12 3 0 1048575 28947 PO- /dev/mvpdbs10
13 3 0 1048575 175794 PO- /dev/mvpdbs11
14 3 0 1048575 166865 PO- /dev/mvpdbs12
15 3 0 1048575 373542 PO- /dev/mvpdbs13
16 3 0 1048575 870402 PO- /dev/mvpdbs14

Continue restore? (y/n)y
Do you want to back up the logs? (y/n)n

****(10 Minutes elapsed)****

Physical restore failed - could not fork server connection

Program over.
INFerbhat3:/apps/informix::

The online.log shows this:

Tue Sep 14 11:55:34 2004

11:55:34 Event alarms enabled. ALARMPROG = '/apps/informix/dba/bin/alarmprog'
11:55:39 DR: DRAUTO is 0 (Off)
11:55:40 Informix Dynamic Server Version 7.31.FD7 Software Serial Number AA
D#J342257
11:55:40 WARNING: Next backup of DBspace rootdbs must be level-0 backup.
11:55:40 WARNING: Next backup of DBspace mvp_dbspace must be level-0 backup.
11:55:40 Informix Dynamic Server Initialized -- Shared Memory Initialized.
11:55:40 Dataskip is now OFF for all dbspaces
11:55:40 Restartable Restore has been ENABLED
11:55:40 Recovery Mode
11:55:40 listener-thread: err = -25572: oserr = 226: errstr = : Network driver
cannot bind a name to the port.
System error = 226.
11:55:40 Attempting to bring listener thread down.

11:55:40 Server stopped.

11:55:40 Informix Dynamic Server Stopped.
11:55:40 mt_shm_remove: WARNING: may not have removed all/correct segments
Tom Danzig
Honored Contributor

Re: Informix ontape problems - "could not fork server connection"

Just a shot in the dark ...

Check available swap with swapinfo -ta and check if there is enough. I have seen instances where there was insufficient swap available to fork a new process.

Your message was "could not fork server connection" so I'm not sure if this is applicable.
daniel m_1
Advisor
Solution

Re: Informix ontape problems - "could not fork server connection"

What version of Informix was the backup taken on?
You can use different O/S versions, but Informix support has always told me the Informix version has to be the EXACT version for the restore as the backup.
Brian Butscher
Frequent Advisor

Re: Informix ontape problems - "could not fork server connection"

Robin,

First thing is to check the online.log. This should give you more information pertaining to the the error. If you find an error in the online.log then use 'finderr xxxx' to get more information from Informix.

Also check the following:
1) 'sqlhosts' file in the etc directory to make sure you have the proper host name, the 'DBSERVERNAME and DBSERVERALIASES should match what you have in the 'etc/onconfig.xxx file.
2) Check for any '.str' files in the /INFORMIXTMP directory, remove them.
3)Check $INFORMIXDIR/release file for shared memory requirements.
4) After you attempt to restore and you get an error, check ipcs. If there are any queues, memory, or shared memory owned by informix, clean them up with the ipcrm -q xxxxx, ipcrm -m xxxxx, or ipcrm -s xxxxx. You will not have enough memory to restart the restore unless you do this.
5) Check the permissions and ownership on the files in the /dev/vginformix directory (assuming you use this directory to create the logical volumes for Informix). Permissions need to be 660, ownership informix:informix for all informix logical volume files created. Make sure user 'informix' has access to that directory and files.

Are you using a cooked or raw database?

Let me know if you still have problems.

Regards,
Brian